1. Field of the Invention
This invention relates to devices that feed envelopes and other sheet-like material from stacks.
2. Background Information
Current estimates place the number of envelopes used annually in the United States at over 100 billion. A significant percentage of these envelopes are used in connection with bulk mailings, and are accordingly filled, addressed and processed by a variety of automated machines. A lynchpin of all automated processes is the automatic envelope inserter. Automatic inserters are large, complex machines that are loaded with contents to be inserted (e.g., individual letter sheets and/or fillers) and envelopes in which these contents are to be inserted. Other machines such as binders, that bind inserts together (into a books, catalogs, newspapers or magazines), presses that apply logos and decoration, addressing machines, and a variety of other machines are also used selectively to process individual sheet-like materials in bulk mailing and other processes. These various devices can be termed generally xe2x80x9cutilization devicesxe2x80x9d as they utilize sheet-like materials that are typically dispensed in stacks.
FIG. 1 shows a high-volume envelope inserter used by industry. The exemplary inserter 100 is a large, modular unit that combines various contents stored in hoppers (not shown) in the rear 102 of the machine and that directs the contents (arrows 104 and 106) onto a raceway 108 downstream (arrow 110) toward a stack of envelopes 112. At each point along the raceway, additional insert sheets are added to the contents. These contents may be folded, or otherwise compacted, to fit within the selected envelope by mechanism within the inserter. Envelopes are drawn from the stack 112, and directed downstream (arrow 114) to a inserting station 116 at which the closed-but-unsealed envelope flaps 118 are opened so that the final contents 120 (shown in phantom for clarity) can be inserted thereinto. The filled envelopes 112 are then transferred further downstream (arrow 124) to a stacking position or further-processing module (not shown).
Industrial inserters are available from a variety of well-known companies including Bell and Howell and Pitney Bowes. One example is the Bell and Howell Imperial(trademark). With reference to the envelope stack 112, the stacking location or xe2x80x9cfeed stationxe2x80x9d 130 consists of a series of upright guide rails 132, 134 that, respectively, contain the four opposing sides of each envelope in the stack. In most commercially available machines, the envelope stack, as well as the hoppers (not shown) for the insert contents, are open at the top and exposed for easy access. This is, in part, because inserters typically consume envelopes in the range of 3000-25000 pieces per hour. Conversely, the contents hopper and envelope feed station only have capacity for a stack of approximately 300-400 pieces. As such, the various stations of the inserted must be constantly monitored and reloaded by one or more individual operators.
With further reference to FIG. 2, the cycle of feed station loading is more-clearly illustrated. A stack of a few hundred blank or pre-printed envelopes 142 is removed from a box 140 of one thousand. The box may be accessed through a top that exposes the envelopes on-edge as shown, or through another opening. In any case, a grouping 150 is lifted manually from the box 140, often bounced one or more times against a flat surface in an attempt to ensure registration, and then deposited (arrow 152) to the feed station 130 onto the stack 112. The envelopes are then drawn out of the stack 112 one at a time using any one of a number of singulating feed techniques. In the exemplary feed station, friction feed rollers 156, 158 and 160 operate in conjunction with a non-rotating gate wheel 162 to singulate and feed envelopes downstream to the insertion location from the stack bottom. Pushers, vacuum belts and sliding tables are also used to singulate envelopes and/or contents according to alternate arrangements.
The above-described stack-loading technique, in which small discrete bundles are transferred from the box to the feed station, can give rise to may different (often recurring) failures. For example, repetitive loading of relatively small bundles of envelopes increases the possibility of a feed failure for a given envelope from the stack based upon the sudden application of significant force to the stack bottom as envelopes are dropped into the feed station. This is an ongoing concern as stacks are typically fed from their bottoms against the entire overlying weight/friction of the remaining stack. In addition, it is critical that envelopes be loaded in only one orientation every time. In other words, flaps must generally be placed face-up, and in a specific direction. Nevertheless, there are at least four different possible orientations in which rectangular envelopes can be loaded into the stackxe2x80x94of which three out of the four orientations are incorrect. Given the continuous and repetitive nature of the loading process, it is not uncommon for an operator to miss-load envelopes fairly regularly. Moreover, the stack orientation of envelopes required by the inserter may be geometrically reversed from that in which the envelopes are removed from the box. This means that the operator must often rotate, flip over, or otherwise reorient the envelopes each time they are loaded. Over a period of time, the repetitive lifting of a heavy stack of envelopes and constant reorienting of this time can fatigue the operator and cause progressive orthopedic injuries. In fact, the related motions involve slitting open a continuous progression of envelope boxes with sharp blades to remove the contents further exasterbates fatigue and possible injury. Finally, the simple monotony of constantly and repeatedly reloading of relatively small bundles of envelopes into an open hopper seems an unavoidable but equally undesirable byproduct of inserter operation.
Prior proposals for increasing the efficiency of envelope and contents stack-loading have included the feeding of envelopes or insert pieces from large bound rolls, such as described in U.S. Pat. No. 5,282,350 to Crowley. Alternatively, the feeding of envelopes from large, palletized balk cassettes has been suggested according to U.S. Pat. No. 5,478,185 to Krantz. However, while these techniques show promise, they require owners of inserting machines to make a large investment to retool the existing install base of machines, which may unacceptably increase production costs thereby straining fragile profit margins. In addition, these techniques may prevent the equipment from being easily returned to conventional bundle-feeding when needed (such as when a small custom job is desired).
Accordingly, it is an object of this invention to provide an system and method for providing a large stack of sheet-like materials, such as envelopes, to a utilization device that reduces the number of stack-loading cycles required by the operator and essentially eliminates direct operator contact with discrete bundles of the materials. This system and method should also reduce the amount of effort spent by an operator in preparing a material supply container (box of envelopes) for use, and should increase the stack capacity of existing utilization devices without requiring substantial refit or retooling or the devices"" feeding components. This system and method should also preferably allow material supply containers to be easily reused with minimal repair or refit. The containers should be collapsible into easily stored and transported shapes.
This invention overcomes the disadvantages of the prior art by providing a system and method for storing and dispensing stacks of sheet-like materials using a container that encloses a large number of stacked, sheet-like materials (such as envelopes) having a common predetermined orientation within the container. The container is arranged with a release mechanism at a dispensing end or opening thereof, arranged so that when the container is mounted in an appropriate sequence on a stacking location/feed station on a utilization device, the container releases its stack into the feed station for use by the utilization device.
In an illustrative embodiment, the feed station can include guides that, in conjunction with the container, enable the container to extend and further guide the stack beyond the top ends of the guides. In this manner, the overall capacity of the utilization device feed station is increased. The feed station is preferably adapted so that it can be readily used in a conventional manner by manual loading of smaller, discrete bundles materials and/or stacks of materials without use of the container if desired.
According to one embodiment, the dispensing end or opening includes a set of folds adapted to fold inwardly toward the inside walls of the container when the container is directed over the guides. This enables the stack to drop onto the feed station guides. The outer dimensions of the container can be sized to allow the container to fit over the guides so that it comes to rest at the bottom of the feed station.
According to another embodiment, the container can comprise a box-like structure having a variety of operator-actuated release mechanisms that normally restrain the stack from passage out of the dispensing end or opening, but based upon a predetermined movement (generally once the dispensing end or opening confronts the opening of the feed station), the dispensing end or opening releases the stack into the feed station. The container may be adapted to define an extended guide for a deeper stack, and appropriate internal structures can be provided to the container to facilitate support and guiding of a deeper stack. In one embodiment the dispensing end or opening of the container includes an interlocking flap closure structure with a series of overlapping tab sections that positively retain the stack against outward movement, but that can be opened by applying a force in an opposing inward direction to unlock the interlocking flaps from each other.
In another embodiment, the container can define any number of non-fully enclosing structures that restrain the breakup of the storage stack until the release mechanism is activated. For example, the container can be a ribbon or wrap that is broken and withdrawn once the stack is deposited in the feed station. The container can be a comb-like structure that supports an edge of the stack, and is withdrawn after deposition in the feed station. Similarly, the container can be a plurality of interconnections between adjacent materials in the stack, that are typically adhesively joined, and broken free at a desired time. The container can also comprise an extended feed surface that may be removable, for causing a waterfall of materials into the feed station from the larger feed surface.
In yet another illustrative embodiment, a container in the form of an envelope-filled cassette is provided. The cassette is arranged with a dispensing end or opening that can be opened by the user or an alternate closure along some or all of the elongated length thereof so that all, or a substantial portion, of the envelope contents can be randomly accessed for manual feeding or other uses. The dispensing end or opening, in one embodiment can be opened by removing the bottom using a tear strip, embedded below the surface of the cassette, that causes the bottom to separate from the remainder of the dispensing cassette by pulling the tear strip away from the circumference of the box. A fixture is located on the stacking location/feed station and defines a receptor for the cassette. The receptor is adapted to support the cassette so that it is suspended out of interfering contact with the workings of the feed station, bridges and maintains continuity between any material previously located at the feed station and the start of feed from the newly mounted cassette, and generally allows visual inspection of the flow of envelopes from the feed station so as to enable change of the cassette at the appropriate time and overall observation of the rate of consumption. To accomplish this interconnection between the receptor and cassette, the receptor includes three or four sides in which opposing sides force the cassette into a proper (squared) orientation. The receptor can include a slanted wall and a straight wall, opposite thereto, in which the slanted wall urges envelopes entering (dropping into) the feed station from the cassette against the straight wall for proper justification of the entering envelopes. The receptor can include, on two opposing walls, sets of flexible guide strips that deflect away from the cassette in the area in which it occupies, but that straighten in an area below the bottom edge of the cassette so as to firmly hold the cassette in place and justify the envelopes along adjacent edges as they leave the cassette bottom. The guides can be adjustable for length and width using a variety of moving and locking mechanisms (for example, slides, thumb screws, etc.). Finally, the cassette can be constructed with a shoulder seam or other key that interacts with a corresponding structure in the receptor in a manner that allows the cassette and receptor to mate only in a desired orientation.